Lubrication system for sewing machines



Feb. 5, 1957 J. G. ATTWOOD LUBRICATION SYSTEM FOR SEWINGMACHINES 4 Sheets-Sheet 1 Filed Dec. 1, 1954 J. G- ATTWOOD was 5 195 R SEWING MACHI Feb LUBRICATION SYSTEM F 4 hee 2 Filed Dec. l, 1954 v lllllllllllllllllllflll! I I llqlllllllllllllll Feb.5,19

J. G. ATTWOOD 2,780,192

LUBRICATION SYSTEM FOR SEWING MACHINES Filed Dec. 1, 1954 4 t heet 5 mmu WMMWW Feb. 5, 1957 J. G. ATTWOOD 2,730,192

LUBRICATION SYSTEM FOR SEWING MACHINES Filed Dec. 1, 1954 4 Sheets-Sheet 4 FIG.4

United States Patent LUBRICATION SYSTEM FOR SEWING MACHINES John G. Attwood, Oak Park, Ill., assignor to Union Special Machine Company, Chicago, Ill., a corporation of Illinois Application December 1, 1954, Serial No. 472,488

11 Claims. (Cl. 112-256) This invention relates to sewing machines and more particularly to industrial machines subject to high speed operation over long periods of time. It is concerned particularly with the effective lubrication of the relatively moving parts in the needle head ofsuch a machine.

In accordance with the invention a supply of lubricant is maintained in a reservoir in the base of the hollow frame of the machine and is distributed from this reservoir to various parts requiring lubrication. Some of the lubricant is delivered through an overhanging hollow arm of the frame to parts within a needle head at the end of the arm. Excess lubricant is collected in a small sump at the bottom of the needle head and this excess is returned to the main reservoir by a novel lubricant return system.

An important object of the present invention has been to provide a fully automatic lubricant return system which operates efficiently and eflfectively to return excess lubricant to the main reservoir under varying operating conditions.

A further object has been to provide a system of the character indicated which is simple, inexpensive, requires a minimum of attention and requires no operating parts in addition to those already present in the machine.

Toward the foregoing ends the machine is provided with a self-starting syphon arrangement for returning the excess lubricant. The arrangement is such that a portion of the lubricant regularly circulated through the frame of the machine, in the form of a mist or the like for the lubrication of various parts, is diverted into a device for starting the syphon into operation whenever the machine is started up after an idle period and as soon as any excess lubricant requiring return to the main reservoir collects in a suitable sump for such excess. This device operates effectively also to return excess lubricant as soon as it accumulates to a desired level in the sump even though the level of the lubricant in the sump drops at times below said desired level. The arrangement may be such furthermore, whenever desired, that the sump is kept substantially dry. For this purpose, means are provided for insuring capillary attraction of the lubricant from the sump into the return tube with the result that all excess lubricant is picked up and an effective air-lock is provided against the intake of air at the intake end of the return tube.

With the foregoing objects, features and advantages of the invention in view, certain illustrative embodiments of the same will now be described in detail in conjunction with the accompanying drawings, in which:

Fig. 1 is a view partly in elevation and partly'in vertical section through a sewing machine embodying the invention;

Fig. 2 is an end elevational view of the machine as seen from the right in Fig. 1, portions of the frame and interior construction being broken away or omitted;

Fig. 3 is an end elevational view of the upper portion of the machine as viewed from the left in Fig. 1, a cover plate for the needle head being largely broken away;

2,780,192 Patented Feb. 5, 1957 ice Fig. 4 is a vertical sectional view through a lubricant level indicator, taken along the line 44 of Fig. 1;

Fig. 5 is a detail view, partly in elevation and partly in vertical section, through a portion of the oil return syphon embodied in the machine;

Fig. 6 is an enlarged detail View, in vertical section, of aportion of the structure shown in Fig. 5 and illustrating a modification; and

Fig. 7 is a detail view, partly in elevation and partly in vertical section, showing a modification at the intake side of the syphon.

Referring now to the drawings, the invention has been illustrated as applied to a machine of the character disclosed in the patent to Peterson et al. No. 2,598,426 granted May 27, 1952. The general construction and operation of the machine will be described only briefly and reference may be had to said Peterson et a1. patent for details.

The machine comprises a frame having a work supporting base 10, a vertical standard 11, and an overhanging arm 12 terminating in a needle 'head 13 above the work supporting base. Within the base of the machine a main rotary drive shaft 14 extends beneath the work support. This shaft extends outwardly from the frame and carries at its outer end a combined handwheel and pulley 15 through which the machine may be driven. A crank element 16 having a spherical crank portion cooperates with a strap at the lower end of a pitman 17, the upper end of this pitman having a strap cooperating with a ball pin extending longitudinally from a needle lever 18 mounted for rocking movement about the axis of a transversely extending shaft 19 within the overhanging arm 12. At its left end (Fig. 1) the needle lever is connected by a link 20 with a block 21 secured to a needle bar 22 mounted for vertical reciprocation within the needle head. A plurality of needles 23 are carried by the lower end of the needle bar, from a position above the work supporting surface of the base to a point heneath the latter as shown in Fig. 1. Cooperating with the needles in the formation of a seam is a looper 24 secured to the upper end of a looper carrier 25 which is mounted for pivotal movement and for transverse rocking movements to impart loop-seizing and shedding and needle avoid movements to the looper. Above the Work support, the illustrative machine is provided with a cover thread laying member 26 having a shank portion 27 secured to a sleeve 28 mounted for oscillation within a bearing provided in the bottom of the needle head. The sleeve 28 surrounds a presser bar 29 carrying a presser foot 30 at its lower end. As will be understood, the presser bar is arranged for vertical movement within the sleeve 28 and is spring urged downwardly to hold the work against the work support and in cooperation with a four-motion feed dog. Means are provided for oscillating the sleeve 28 to impart the desired cover thread laying movements to the member 26. For this purpose a pitman 31 (Fig. 3) has a strap at one end cooperating with a ball pin extending laterally from the sleeve 28, adjacent its upper end, and having a strap at its opposite end cooperating with a ball pin extending from a downwardly extending arm 32 secured to a rock shaft 33. The latter extends longitudinally of the overhanging arm adjacent the rear face thereof and has secured thereto, within the upper portion of the vertical standard, an arm 34. A pitman 35 (Fig. 2) has a strap at its upper end cooperating with a pin adjustably mounted along a slot provided in the arm 34. At its lower end the pitman 35 carries a strap cooperating with a spherical eccentric 36 carried by the shaft 14.

Within the base of the machine, below the vertical standard, there is provided an oil reservoir 37 (Fig. 1) which communicates with a further reservoir 38 which extends beneath a portion of the work supporting surface of the base. The reservoirs 37 and 38 are in open communication by means of one or more passages 39. The lubricant is introduced into the reservoir to about the level indicated in Fig. 1 and this is engaged by downwardly extending arms or fingers 40 and 41 carried at the lower ends of the pitmen 17 and 35, respectively. In the course of operation of the shaft 14 a lubricant mist is thus dispersed throughout the vertical standard to lubricate various bearing surfaces therein and some of this mist is delivered to the needle lever 18 which, by virtue of its downward inclination toward the needle head, serves to deliver some of the lubricant into the needle head. The lubricant so delivered collects in a sump 42 at the bottom of the needle head from which it is delivered to various points requiring lubrication. Distribution of the lubricant to the desired points is effected by means of a plurality of wicks 43 having their lower ends resting upon the bottom surface of the needle head sump and which extend upwardly through a tube 44 to a distributing head 45. A plurality of wick retaining tubes 46 serves to deliver the lubricant from the head to the various points to be lubricated.

In the course of more or less continuous operation of the machine an excessive amount of lubricant will be delivered to the needle head and means are, therefore, provided for returning the excess above a predetermined amount to the rservoirs 37 and 38. For this purpose there is provided, in accordance with the invention, a special self-starting syphon arrangement having a return tube of suitable diameter, preferably between A and /8 inch internal diameter. This syphon tube has a downwardly extending leg 47 having an inlet end disposed a suitable distance above the bottom of the needle head. The location of the intake end of the tube may be selected to conform with a desired level of lubricant in the sump of the needle head. Leg 47 of the syphon tube extends into a substantially horizontal portion 43 Which extends lengthwise through the overhanging arm. Portion 48 is preferably inclined downwardly at a small angle from the needle head toward the vertical standard so as to avoid delivery of lubricant by gravity in the opposite direction either along the inside or the outer surface of the tube.

Within the vertical standard the portion 48 of the tubing extends into a substantially horizontally projecting stem 49 of a T-fitting. A lubricant tight and air tight connection is provided between the tubing 48 and the stem 49 by means of a screw cap 58 having threaded engagement with the end of the stem 49 and which bears against a spherical or double frusto-conical enlargement 51 on the tubing 48. The latter is preferably formed of rass and the enlargement may, therefore, be forced into a good tight fit with the end of the stem 48 and the inner end of the opening through the cap 50.

An upwardly extending branch 52 of the T-fitting has inserted therein the lower end of a short tube 53. The latter is retained in air-tight connection With the branch 52 by virtue of an enlargement 54 on the tube 53 which is forced into the outer end of the branch 52 by means of a screw cap 55. Mounted upon the upper end of the tube 53 is an oil collecting cup 56 which is adapted to retain a suitable quantity of lubricant to provide for the self-starting of the syphon.

The T-fitting has a downwardly extending branch 57 which is connected in air-tight relation with a downwardly extending tube 53. Screw cap 59 serves to retain the tube 58 in the desired relation to the branch 57, in the same manner as explained in relation to the caps and 55. Tube 58 extends downwardly through the vertical standard and terminates at a point slightly above the level of the lubricant in the reservoir 37.

For retaining the spyhon arrangement described above in proper position, the tube 58 has soldered or brazed thereto a clamping block 60 adapted to be clamped about a sleeve 61 surrounding a shaft 62 suitably journaled in the vertical standard and extending from front to rear thereof. Clamp 60 may suitably be of split sleeve construction and clamped upon the sleeve 61 by means of a screw 63.

Oil is continuously supplied to the feed cup 56, so long as the machine is in operation, by means of a trough element 64 which is arranged to collect some of the lubricant dispersed in the manner hereinabove explained. The trough has a laterally extending arm or shelf 65 at one end which is secured by a screw 66 to the lower end of a boss 67 provided on the inner surface of a removable cap 68 at the top of the vertical standard. It will be understood that any excess lubricant delivered to the cup 56 will simply overflow the latter and be returned to the reservoir 37.

To bring about the proper operation of the improved syphon system it is important to observe certain relationships between the various parts. The downwardly extending leg 58 must, of course, be longer than the intake leg 47 and must terminate at a level below the intake end. Also, it is important to provide a frictional resistance to the flow of oil from the cup 56 so as to prevent'the delivery of oil from this cup through the laterally extending portion 48 and the downwardly extending leg 47 of the syphon. For this purpose, the frictional resistance should be somewhat greater than the combined lubricant heads of the leg 47 and of the lubricant from its level within the cup 56 to the junction of the laterally extending stem 49. This frictional resistance may be supplied by providing a felt disc 69 at the bottom of the cup 56 to extend over the outlet from the cup. This felt disc may be retained by a spring ring '70. In lieu of or in addition to the provision of the felt disc 69, the short tube 53 may be provided with a suitable restriction, as indicated at 71 in Fig. 6, to provide the desired frictional resistance to the flow of the lubricant from the cup.

Another desirable condition to be maintained is that the capillarity is such that the resistance to the passage of air provided at the bottom of the cup 56 by means of the felt disc 69 or the restriction 71, or both, should be greater than the lubricant head below the junction of the stem 49 of the T-fitting with the two vertical branches thereof plus the head of lubricant between this junction and the felt disc or other means for restricting the flow of lubricant from the cup. A disc 69 which is /2 in diameter and thick formed of SAEF-50 felt, or a. restriction 71 which is A" long and has an opening in diameter, have been found to produce good results, but it should be understood that the invention is not restricted to the use of these dimensions or the particular type of felt indicated.

in the operation of the system, assuming that the syphon carries no oil but is filled with air, the filling of cup 56 by the operation of the machine in the manner explained will cause alternate drops of oil and air bubbles to descend the delivery leg 58. The air bubbles are formed by air withdrawn from the tubing 48 as each drop of oil passes the junction of the T-fitting. As this operation continues and the delivery leg becomes substantially filled with the oil and air the syphon action will begin and cause withdrawal of any excess lubricant from the sump in the needle head. As the oil so withdrawn fills the syphon it assumes its normal operation of transferring the lubricant from the needle head sump to the main reservoir.

If desired, appropriate capillarity permitting the passage of lubricant but preventing the introduction of air may be provided at the inlet end of the syphon. This may be done either by an appropriate restriction of the inlet end of the leg 47 or by the application of a cap 72 formed of felt or other porous material over the inlet end of such leg. When such capillarity is provided and other conditions are observed, as explained above, the syphon may be kept filled even though the level of the lubricant in the sump in the needle head may fall below the lower end of the inlet of the leg 47. When a felt or similar cap is provided to introduce the desired capillarity, this may serve to draw into the tube any oil remaining in the needle head sump even when the machine is at rest. Should it be desired to maintain the sump in an empty condition whenever the machine is at rest the felt cap may extend to and rest upon the bottom wall of the sump. However, when it is not important to remove all oil from the sump the cap may be omitted or its lower end may be located some distance above the bottom wall of the sump.

The tubing used for the syphon may have an inside diameter of between 19, and /8 of an inch, depending upon the lubricant return capacity desired. In a typical unit the leg 47 may have a height of 3" while the leg 58 below the junction of the T may have a height of 6" and the cup 56, when full, may provide a head of 2" above the junction of the T. Upon operating a machine equipped with a unit of this sort, utilizing tubing having an inside diameter of fl th of an inch, it was found that 30 drops of oil per minute were pulled from the sump in the needle head and delivered to the main reservoir. This was without the provision of any capillary means, such as the cap 72 or a plug or restriction at the lower end of the leg 47. On the other hand, when cap 72 was applied to the same unit it was found that the syphon was capable of pulling about 8 drops of oil per minute from the needle head sump. In general, it may be said that the greater capacity of the syphon is desirable but, as explained, it is sometimes important to drain the needle head sump completely of oil and to accomplish this it is necessary to provide a porous cap 72, or a porous plug inserted in the lower end of the inlet leg 47 of the syphon, or some similar arrangement.

When capillarity is provided at the inlet end of the leg 47 this should be of such character as to overcome the tendency of air to enter the syphon under the differential head determined by the length of leg 58 from the junction of the T-fitting minus the head in the leg 47, i. c. three inches of oil in the typical unit mentioned above. A cap formed of SAE-F-IO felt has been found highly satisfactory for the purpose, but it should be understood that felts of other types could be used.

As shown in Fig. 3 the needle head may be provided with a transparent oil cap 73 formed of Lucite or the like through which the level of the oil in the needle head sump may be noted. The score lines extending across the face of the plug indicate the approximate level of the lower end of the inlet leg 47.

Preferably, also, an arrangement is provided for indicating, at a conveniently observable position, the level of the lubricant in the reservoirs 37 and 38. For this purpose a chamber 74 (Figs. 1 and 4) may be provided within the reservoir 38 and a float 75 may be positioned for vertical movement within this chamber. A rod or stem 76 extending upwardly from the float may have its upper end 77 visible through a transparent disc or plug 78 formed of Lucite or the like. The upper end of the stem is free to rise and fall within a diametric opening 78:: extending through the plug. Suitable scoring lines 79, provided across the outer face of the transparent plug may provide an indication of the upper and lower lirnts of the desired level of the lubricant within the main reservoirs. To facilitate free movement of air into and out of the interior of the chamber 74, the circular wall of the latter may be provided with an opening 80 above the top of the float.

While an illustrative embodiment of the invention has been described in considerable detail and certain modifications thereof have been suggested, it will be understood that other changes may be made in the construction and arrangement of the several parts within the scope of the appended claims. Thus, while the T-fitting arrangement by which the syphon priming cup isdiposed in vertical alignment with the leg 58 is highly advantageous and preferred, the priming cup could, if desired, be arranged to deliver the priming oil into the portion 48 of the syphon tube at aconvenient point.

What is claimed is:

1. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said sump, a substantially horizontal portion and a long -leg extending downwardly to a point adjacent said reservoir, lubricant receiving meansc'ommunicating with said long leg adjacent its upper end and extending up-" wardly therefrom, and means for directing lubricant distributed by said operating means into said lubricant receiving means.

2. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said s ump, a substantially horizontal portion and a long leg extending downwardly to a point adjacent said reservoir, lubricant receiving means communicating with said long leg adjacent its upper end and extending upwardly therefrom, and means for directing lubricant distributed by said operating means into said lubricant receiving means, the connection between said lubricant receiving means and said long leg having a frictional resistance to the flow of lubricant therethrough sufficient to overcome the combined lubricant head of the lubricant in said receiving means and of the lubricant in said short leg.

3. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said sump, a substantially horizontal port-ion and a long leg extending downwardly to a point adjacent said reservoir, lubricant receiving means communicating with said long leg adjacent its upper end and extending upwardly therefrom, and means for directing lubricant distributed by said operating means into said lubricant receiving means, the connection between said lubricant receiving means and said long leg being provided intermediate said means and said leg with a frictional resistance to the flow of lubricant therethrough sufficient to overcome the combined lubricant head of the lubricant in said receiving means and of the lubricant in said short leg and having a resistance to the introduction of air greater than the total vertical lubricant head from the bottom of the long leg to the said frictional resistance.

4. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said sump, a substantially horizontal portion and a long leg extending downwardly to a point adjacent said reservoir, lubricant receiving means, means above said long leg for directing lubricant distributed by said operating means into said lubricant receiving means, connections from said lubricant receiving means to said long leg adjacent the upper end of the latter, and capillary means associated with said connections for creating frictional resistance to the flow of lubricant from said receiving means to said long leg, said capillary means being constructed and arranged to provide greater resistance to flow through said connection than the combined head of the lubricant in said receiving means and in said short leg.

5. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said sump, a substantially horizontal portion and a long leg extending downwardly to a point adjacent said reservoir, lubricant receiving means, means above said long leg for directing lubricant distributed by said operating means into said lubricant receiving means, connections from said lubricant receiving means to said long leg adjacent the upper end of the latter, and capillary means associated with said connections for creating frictional resistance to the flow of lubricant from said receiving means to said long leg, said capillary means being constructed and arranged to provide a resistance to the passage of air greater than the total vertical lubricant head from the bottom of the long leg to said capillary means.

6. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said sump, a substantially horizontal portion and a long leg extending downwardly to a point adjacent said reservoir, said substantially horizontal portion being disposed at a small angle downwardly from said short leg to said long leg, lubricant receiving means above said long leg communicating with said long leg adjacent the upper end thereof and extending upwardly therefrom, and means for directing lubricant distributed by said operating means into said lubricant receiving means.

7. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a' syphon tube having a short leg extending downwardly into said sump, a substantially horizontal portion and a long leg extending downwardly to a point adjacent said reservoir, the lower end of said short leg having a capillary element therein adapted to lift lubricant from said sump into said syphon tube and prevent the introduction of air into said tube, lubricant receiving means above said long leg communicating with said long leg adjacent the upper end thereof and extending upwardly therefrom, and means for directing lubricant distributed by said operating means into said lubricant receiving means.

8. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said sump, a substantially horizontal portion and a long leg extending downwardly to a point adjacent said reservoir, the lower end of said short leg having a cap thereover arranged to engage the bottom of said sump, said cap being formed of porous material serving to lift and retain in the lower end of said short leg by capillary action lubricant delivered to said sump, said cap serving to prevent the introduction of air itno said tube, lubricant receiving means above said long leg communicating with said long leg adjacent the upper end thereof and extending upwardly therefrom, and means for directing lubricant distributed by said operating means into said lubricant receiving means.

9. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said sump, a substantially horizontal port-ion and a long leg extending downwardly to a point adjacent said reservoir, lubricant receiving means above said long leg communicating with said long leg adjacent the upper end thereof and extending upwardly therefrom, and means for directing lubricant distributed by said operating means into said lubricant receiving means, the connection between said lubricant receiving means and said long leg having a felt plug therein arranged to provide a frictional resistance to the flow of lubricant therethrough sutficient to overcome the combined lubricant head of the lubricant in said receiving means and of the lubricant in said short leg.

10. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said sump, a substantially horizontal portion and a long leg extending downwardly to a point adjacent said reservoir, lubricant receiving means above said long leg communicating with said long leg adjacent the upper end thereof and extending upwardly therefrom, and means for directing lubricant distributed by said operating means into said lubricant receiving means, the connection between said lubricant receiving means and said long leg having a felt plug therein arranged to provide a frictional resistance to the flow of lubricant therethrough sufiicient to overcome the combined lubricant head of the lubricant in said receiving means and of the lubricant in said short leg and having a resistance to the passage of air greater than the combined head of the lubricant from the bottom of said lubricant receiving means to the lower end of said long leg.

11. In a sewing machine a hollow frame having a lubricant retaining reservoir, operating means within said frame for distributing lubricant to parts requiring lubrication therein, a sump at a level higher than said reservoir for collecting excess lubricant, and means for returning lubricant from said sump to said reservoir comprising a syphon tube having a short leg extending downwardly into said sump, a substantially horizontal portion and a long leg extending downwardly to a point adjacent said reservoir, a funnel-like lubricant receiving means above said long leg communicating with said long leg adjacent the upper end thereof and extending upwardly therefrom, and means for directing lubricant distributed by said operating means into said lubricant receiving means, said funnel-like lubricant receiving means having a porous capillary element extending across the discharge end thereof to retard the discharge of lubricant from said lubricant receiving means.

References Cited in the file of this patent UNITED STATES PATENTS 42,304 Naglee Apr. 12, 1864 117,750 De Lagillardie Aug. 8, 1871 1,512,159 Brinton Oct. 21, 1924 2,393,815 Sauer et a1 Jan. 29, 1946 

